Computer disk drives are dynamic magnetic storage units having high bit densities. They are very high precision units requiring close dimensional tolerances in manufacturing and are complex and delicate mechanically. They generally comprise rotatable memory discs, transducer heads, and in one type, a pivotally mounted magnetically driven actuator arm assembly supporting the transducer heads for bidirectional arcuate movement over the discs.
Prior art disc drives of the pivoting type have been difficult to assemble and to disassemble. Frequently the transducer heads and supporting arms are part of an integral pivotally mounted actuator arm assembly which includes the lubricated bearing structure. Removal of this assembly for testing or replacement of heads involves a major disassembly of the structure. In other arrangements the arms which carry the transducer heads may be removable individually from a pivotally mounted actuator member, but the electrical connections must be detached at the transducer head wires while in proximity to the rest of the structure which is difficult and the arms and heads can not be tested as a unit until after complete reassembly of the structure. Mechanical tolerances in a drive with a large number of discs can be difficult to deal with, particularly with respect to relative heights of the discs and arms.
In other instances where the designs provide for detachment of the arms which support the heads individually, shims are used to achieve the center-to-center spacing of the arms and heads to correspond with the axial center-to-center spacing of the discs. In still other instances, the arms are attached and adjusted individually using a beveled drive bolt. This is a technique that requires precise control of bolt torque and which is very time consuming when there are a large number of discs and heads.